Our planet is roughly 4.5 billion years old. Our human ancestors appeared on Earth around 66 million years ago. Still, as we know ourselves today, humans have only existed for the last 2 million years, the vast majority of that time as hunter-gatherers.
Humans may have begun to grow crops on the Sea of Galilee’s shores about 23,000 years ago. However, agriculture proper did not start to develop until 12,000 years ago when hunter-gatherers in the ‘Fertile Crescent’ began growing wild varieties of crops like peas, lentils and barley. They also herded wild animals like goats and oxen in the region.
Historians disagree as to why our ancestors made the structural shift from hunting and gathering to farming. Some argue that a changing climate left them no alternative but to seek alternative sources of foods. Some suggest the transition was more a result of our perpetual drive to improve our condition. Others even suggest that a love of beer drove them to give up their nomadic lifestyles. Archaeologists estimate that 40 per cent of early wheat production went to make beer—the oldest barley beer dates to 3400 BC.
In broad-brush terms, historians divide agricultural progress into three stages. The First Agricultural Revolution defines the move from hunting-gathering to farming that occurred 7-10,000 years ago. The Second Agricultural Revolution refers to the mineral fertilisers and the industrialisation of farming and farm processing in the 19th century. We are still living through the Third Agricultural Revolution, or the ‘Green Revolution’, that began in the middle of the 20th century. It involved improved crop yields through breeding and the introduction of agricultural inputs such as fertiliser and pesticides.
Farming changed little during the first 10,000 years of human history. Farmers regularly left fields fallow, and animal manure was the sole fertiliser. In the early 1800s, scientists began to understand that inorganic minerals such as nitrogen, potassium, lime, and phosphoric acid could replenish depleted soils.
The search for fertiliser led merchants and scientists to the dry seabird islands off the South American and South African coasts, where immense deposits of bird droppings, rich in nitrogen and phosphorus, had accumulated over centuries. Guano mining became a profitable business. Between 1840 and 1880, guano nitrogen made a vast difference to European agriculture, but the best deposits were soon exhausted. However, miners found rich mineral nitrate deposits in Chile, and nitrates gradually replaced guano in the late 19th century.
In The Omnivore’s Dilemma, Michael Pollan writes that the great turning point in the modern history of agriculture can be dated to the day in 1947 when a munitions plant in Alabama switched away from making explosives to make chemical fertiliser instead. He explains that at the end of World War II, the US government found itself with a surplus of ammonium nitrate, the principal ingredient in making explosives. Ammonium nitrate is an excellent source of nitrogen for plants. Chemical fertilisers and pesticides were the product of the US government’s effort to convert its war machine to peacetime purposes.
Even though the Earth’s atmosphere is about 80 per cent nitrogen, nitrogen atoms have to be split and joined to hydrogen atoms (‘fixed’) to make fertiliser or bombs. A German Jewish chemist named Fritz Haber worked out how to do that in 1909. Before he made that discovery, all the usable nitrogen on Earth had to be fixed by soil bacteria or electrical lightning, which breaks down nitrogen bonds in the atmosphere.
In his book, Enriching the Earth: Fritz Haber, Carl Bosch and the Transformation of World Food Production, Vaclav Smil explains that ‘there is no way to grow crops and human bodies without nitrogen’. Without Haber’s invention, the small amount of nitrogen that bacteria and lightning alone could release would have limited the number of people that agriculture could support.
In his book, Mr Smil argues that the Haber-Bosch process for fixing nitrogen (Bosch commercialised Haber’s idea) was the most important invention of the 20th century. He estimates that 40 per cent of the people on Earth today would not be alive without Haber’s invention. Without synthetic fertiliser, billions of people would never have been born.
Fritz Haber won the Nobel Prize in 1918 for ‘improving the standards of agriculture and the well-being of mankind’, but, since then, he has since largely been airbrushed out of history. During the First World War, he helped the German war effort by making bombs from synthetic nitrate. Worse, he also developed poison gases, including Zyklon B, used in the Nazi concentration camps.
The Haber-Bosch process works by combining nitrogen and hydrogen gases under immense heat and pressure, supplied by electricity. The hydrogen is provided by oil, coal or, most commonly today, natural gas. As such, Michael Pollan argues that once humanity had acquired the power to fix nitrogen, the basis of soil fertility shifted from a total reliance on the energy of the sun to a new dependence on fossil fuel.
Farming, which had historically always been a process of converting sunlight into food, has become a process of converting fossil fuels into food. More than half of the world’s supply of usable nitrogen is now human-made—and farmers use more than half of all the synthetic nitrogen made today to grow just one crop: corn.
Some excess nitrogen evaporates into the air, acidifying the rain and contributing to global warming. Some seep down to the water table and the rivers. Mr Pollan writes:
‘The ultimate fate of the nitrates spread in Iowa or Indiana is to flow down the Mississippi into the Gulf of Mexico, where their deadly fertility poisons the marine ecosystem. The nitrogen tide stimulates the wild growth of algae, and the algae smother the fish, creating a ‘hypoxic’, or dead, zone as big as New Jersey–and still growing. By fertilising the world, we alter the planet’s composition of species and shrink its biodiversity.’
He is right, of course. The world would be a very different place if it were not for the advances in agriculture and agricultural technology that occurred over the past century. Admittedly it would probably be less polluted, and we might eat better, but two out of five of us probably wouldn’t be here. And of the remaining three, at least one would go to bed hungry every night.
Some might argue that the world would be a better place if there were 40 per cent fewer of us on the planet. But, personally, I am happy to be here.
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This blog is the first part in a series of ‘long reads’ that I have called: ‘Food Doesn’t Have to Cost the Earth’.
Image from Pixabay